The vessel shown is formed by bending a plate to nearly a complete circle and then riveting a second plate to close it. The ends are then closed. The vessel has a diameter of D = 143 mm and a thickness of t = 4 mm and a length of 800 mm. The rivets are 10 mm in diameter, spaced a distance s = 24.4 mm apart, and have an average shear strength of 35 MPa. Determine the maximum internal pressure in MPa if the rivets are not to shear.